1. Field of the Invention
The present invention relates to dyeing apparatus, and more particularly to a beam for winding thereon materials, such as textiles, to be treated with dyeing liquid in such apparatus.
2. Prior Art
Dyeing apparatus is known which has a hollow perforated beam for winding thereon textile materials, such as tapes woven or knit of yarns at least partially including synthetic fibers, to be treated with dyeing liquid. A common problem with the known apparatus is that because of the thermoplatic characteristics of such textile materials, the materials would shrink to a considerable extent to become tightened firmly over the holes in the periphery of the beam due to high temperature and high pressure during dyeing, causing non-smooth flow of the dyeing liquid, which would result in non-uniform treatment of the roll of the textile materials with different shades and hues both radially and axially of the roll.
To eliminate such uneven treatment, it has been proposed, as disclosed in Japanese Patent Publication (Kokoku) No. 43-14646, to cover the periphery of a hollow perforated tube with a cushion of polyurethane foam, knit cloth or Japanese paper for winding thereon the textile materials. The cushion not only serves to absorb the extent to which the textile materials shrink due to heat, but also serves to equalize the liquid flow. However, the cushion must be replaced with a new one upon each and every use, making the operation of the prior apparatus time-consuming and expensive. Also the used cushions must be disposed of with careful attention from a view point of protection against environmental pollution.